Bacterial vs. viral pharyngitis

Although streptococcal pharyngitis cannot be accurately diagnosed by symptoms or a physical exam alone, there are certain clues that can help you determine if a sore throat is bacterial in nature. Strep often produces white patches in the throat and on the tonsils, as well as red, swollen tonsils. Pus may be seen in the back of the throat.
CDC: Get 2013-2014 flu shot now

CDC: Get 2013-2014 flu shot now

Symptoms like coughing and postnasal drip can cause pharyngitis, but are less likely to occur with strep. When congestion, runny nose and other cold symptoms accompany a sore throat, a virus is likely responsible.

Swollen and tender lymph nodes in the neck are another symptom of streptococcal pharyngitis.

Colds sometimes cause a fever, but it these are generally low grade in nature. High-grade fevers over 101 degrees Fahrenheit raise the likelihood that strep is causing a sore throat. However, the bacteria can still be present with little or no fever.

If streptococcal pharyngitis goes untreated it can lead to potentially serious complications including scarlet fever (pictured above), rheumatic fever, sinusitis, mastoiditis, glomerulonephritis and guttate psoriasis.

Performing a rapid strep test in-office is the quickest way to determine whether a patient with pharyngitis needs an antibiotic or not. Most of these tests have a 95% sensitivity and a 98% specificity, so although they are highly accurate it is still possible to miss some cases. Because of this, all negative swab specimens should be sent for culture to confirm the absence of strep bacteria.

It is important that clinicians differentiate between bacterial and viral forms of pharyngitis. Inappropriate antibiotic use, particularly for viral respiratory infections, is one of the main factors driving recent increases in antimicrobial resistance. Studies have demonstrated that limiting antibiotic use, particularly macrolides, can reduce emerging resistance among bacterial pathogens, including sore throat-causing streptococcus pneumoniae.

View the slideshow and learn more about practicing good antimicrobial stewardship by knowing when to prescribe antibiotics or if other over-the-counter remedies are appropriate.

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